Research of synthesis and neural network training on double quantum dot colorimetric fluorescent probe for freshness detection

doi:10.1007/s11705-024-2471-8

2024, Vol. 18

Issue (10) : 120 https://doi.org/10.1007/s11705-024-2471-8

Research of synthesis and neural network training on double quantum dot colorimetric fluorescent probe for freshness detection

Caihong Lv^1,², Yuewei Zheng¹, Zhihao Guan¹, Jun Qian², Houbin Li²(

), Xinghai Liu¹(

)

¹. Hubei Engineering Technology Research Center of Spectrum and Imaging Instrument, Electronic Information School, Wuhan University, Wuhan 430072, China
². School of Nursing, Wuhan University, Wuhan 430072, China

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Abstract

There are many disadvantages such as small detection range and environmental restrictions on application conditions, when the single quantum dot powder or solution is used for fluorescent probe detection. In this paper, the blue fluorescent silicon quantum dots and green fluorescent carbon quantum dots were prepared, and their fluorescence color changes after mixing in different proportions were investigated under different pH conditions. When the two quantum dots were mixed with a concentration of 0.1 mg·mL^–1 and a mass ratio of 1:1, the fluorescence color change could be better displayed at a pH from 1 to 14. Meanwhile, the double quantum dots were prepared into two forms (ink and film), successfully realizing the device application of the fluorescent probe. The films and inkjet-printed labels were used to test the spoilage of food (pork, milk, etc.), and the color change data of the labels were collected during the spoilage test. These data were used for neural network training to predict the spoilage changes of foods.

Keywords silicon quantum dots carbon quantum dots fluorescent probe pH freshness

Corresponding Author(s): Houbin Li,Xinghai Liu

Just Accepted Date: 08 May 2024 Issue Date: 18 July 2024

Cite this article:

Caihong Lv,Yuewei Zheng,Zhihao Guan, et al. Research of synthesis and neural network training on double quantum dot colorimetric fluorescent probe for freshness detection[J]. Front. Chem. Sci. Eng., 2024, 18(10): 120.

URL:

https://academic.hep.com.cn/fcse/EN/10.1007/s11705-024-2471-8
https://academic.hep.com.cn/fcse/EN/Y2024/V18/I10/120

Tab.1 Formula of buffer solution for pH from 1 to 14

Fig.1 TEM of (a) B quantum dots and (b) G quantum dots (scale: 20 nm); particle size distribution histogram of (c) B quantum dots and (d) G quantum dots.

Fig.2 FTIR spectra of B quantum dots (B-QDs) and G quantum dots (G-QDs).

Fig.3 (a) Fluorescence spectra of two quantum dot solutions; the actual pictures of (b) two quantum dot solutions, (c) G quantum dot powders and (d) B quantum dot powders under sunlight and UV lamp excitation.

Fig.4 Fluorescence spectra of B quantum dots, G quantum dots and their mixed solutions with different proportions.

Fig.5 (a) The fluorescence spectra of the mixed double quantum dot solutions in the pH range from 1 to 14 and the photos under 365 nm ultraviolet light; (b) UV-vis of mixed double quantum dot solutions with the pH from 1 to 14.

Fig.6 Actual effects of (a) fluorescent film and (b) fluorescent ink after inkjet printing under sunlight and ultraviolet lamp excitation. Sample 1 is a polyurethane film with quantum dots and sample 2 is a polyurethane film without quantum dots.

Fig.7 Pictures of pork and fluorescent film label under (a) daylight and (b) ultraviolet light; (c) picture of pork and fluorescent film under ultraviolet lamp after 96 h; (d) a schematic diagram of the data acquisition of the initial color and the fluorescent color after 96 h of the fluorescent film label by the self-programmed MATLAB program.

Fig.8 Pictures of milk and fluorescent ink label under (a) daylight and (b) ultraviolet light; (c) picture of milk and fluorescent ink labels under ultraviolet lamp after 96 h; (d) the schematic diagram of the data acquisition of the initial color and the fluorescent color of the fluorescent ink label after 96 h by the self-programmed MATLAB program.

Fig.9 (a) Changes of the fluorescence color of the fluorescent film label for pork; (b) training set of the neural network of the fluorescent film label; (c) test set of the neural network for fluorescent film labels.

Fig.10 (a) Changes of fluorescent color of fluorescent ink label for milk; (b) training set of the neural network of the fluorescent ink label; (c) test set of the neural network for fluorescent ink labels.

1	T Ghosh , R Sahoo , S K Ghosh , P Banerji , N C Das . Simplistic hydrothermal synthesis approach for fabricating photoluminescent carbon dots and its potential application as an efficient sensor probe for toxic lead(II) ion detection. Frontiers of Chemical Science and Engineering, 2023, 17(5): 536–547 https://doi.org/10.1007/s11705-022-2239-y
2	B K John , T Abraham , B Mathew . A review on characterization techniques for carbon quantum dots and their applications in agrochemical residue detection. Journal of Fluorescence, 2022, 32(2): 449–471 https://doi.org/10.1007/s10895-021-02852-8
3	N Li , Y Zhang , P Li , B Zhu , W Wang , Z W Xu . Enhanced permeability and biofouling mitigation of forward osmosis membranes via grafting graphene quantum dots. Frontiers of Chemical Science and Engineering, 2023, 17(10): 1470–1483 https://doi.org/10.1007/s11705-023-2329-5
4	J R Casey , S Grinstein , J Orlowski . Sensors and regulators of intracellular pH. Nature Reviews. Molecular Cell Biology, 2010, 11(1): 50–61 https://doi.org/10.1038/nrm2820
5	J Han , K Burgess . Fluorescent indicators for intracellular pH. Chemical Reviews, 2010, 110(5): 2709–2728 https://doi.org/10.1021/cr900249z
6	Y Wang , B Tang , S Zhang . A visible colorimetric pH sensitive chemosensor based on azo dye of benzophenone. Dyes and Pigments, 2011, 91(3): 294–297 https://doi.org/10.1016/j.dyepig.2011.03.003
7	P T Snee , R C Somers , G Nair , J P Zimmer , M G Bawendi , D G Nocera . A ratiometric CdSe/ZnS nanocrystal pH sensor. Journal of the American Chemical Society, 2006, 128(41): 13320–13321 https://doi.org/10.1021/ja0618999
8	X Zhang , Z Li , T Zhou , Q Zhou , Z M Zeng , X D Xu , Y G Hu . A quantum dot-spore nanocomposite pH sensor. Talanta, 2016, 150: 184–189 https://doi.org/10.1016/j.talanta.2015.12.029
9	X Ji , G Palui , T Avellini , H B Na , C Y Yi , K L Jr Knappenberger , H Mattoussi . On the pH-dependent quenching of quantum dot photoluminescence by redox active dopamine. Journal of the American Chemical Society, 2012, 134(13): 6006–6017 https://doi.org/10.1021/ja300724x
10	A Deb , A Konwar , D Chowdhury . pH-responsive hybrid jute carbon dot-cotton patch. ACS Sustainable Chemistry & Engineering, 2020, 8(19): 7394–7402 https://doi.org/10.1021/acssuschemeng.0c01221
11	X Miao , D Qu , D Yang , B Nie , Y K Zhao , H Y Fan , Z C Sun . Synthesis of carbon dots with multiple color emission by controlled graphitization and surface functionalization. Advanced Materials, 2018, 30(1): 1704740 https://doi.org/10.1002/adma.201704740
12	H Dang , L Huang , Y Zhang , C F Wang , S Chen . Large-scale ultrasonic fabrication of white fluorescent carbon dots. Industrial & Engineering Chemistry Research, 2016, 55(18): 5335–5341 https://doi.org/10.1021/acs.iecr.6b00894
13	L Vallan , E P Urriolabeitia , F Ruiperez , J M Matxain , R Canton-Vitoria , N Tagmatarchis , A M Benito , W K Maser . Supramolecular-enhanced charge transfer within entangled polyamide chains as the origin of the universal blue fluorescence of polymer carbon dots. Journal of the American Chemical Society, 2018, 140(40): 12862–12869 https://doi.org/10.1021/jacs.8b06051
14	X Wu , B Zhao , J Zhang , H Xu , K Q Xu , G Chen . Photoluminescence and photodetecting properties of the hydrothermally synthesized nitrogen-doped carbon quantum dots. Journal of Physical Chemistry C, 2019, 123(42): 25570–25578 https://doi.org/10.1021/acs.jpcc.9b06672
15	Y Zhu , Y Yao , Z Chen , Z T Zhang , P Zhang , Z F Cheng , Y F Gao . WO3 quantum dot photochromical film. Solar Energy Materials and Solar Cells, 2022, 239: 111664 https://doi.org/10.1016/j.solmat.2022.111664
16	I Valais , C Michail , C Fountzoula , D Tseles , P Yannakopoulos , D Nikolopoulos , A Bakas , G Fountos , G Saatsakis , I Sianoudis . et al.. On the response of alloyed ZnCdSeS quantum dot films. Results in Physics, 2017, 7: 1734–1736 https://doi.org/10.1016/j.rinp.2017.05.011
17	Y Wang , M Shang , Y Wang , B W Cui , Z J Qiu , H Li , Y X Wang . Polyimide composite films reinforced by graphene quantum dots. Fullerenes, Nanotubes, and Carbon Nanostructures, 2022, 30(6): 683–691 https://doi.org/10.1080/1536383X.2021.2011237
18	T Wang , C Zhou , X Zhang , D Xu . Waterborne polyurethanes prepared from benzophenone derivatives with delayed fluorescence and room-temperature phosphorescence. Polymer Chemistry, 2018, 9(11): 1303–1308 https://doi.org/10.1039/C7PY01995E
19	T Xi , L Tang , W Hao , L L Yao , P Cui . Morphology and pervaporation performance of ionic liquid and waterborne polyurethane composite membranes. RSC Advances, 2018, 8(14): 7792–7799 https://doi.org/10.1039/C7RA13761C
20	T Han , J W Lam , N Zhao , M Gao , Z Y Yang , E G Zhao , Y P Dong , B Z Tang . A fluorescence-switchable luminogen in the solid state: a sensitive and selective sensor for the fast “turn-on” detection of primary amine gas. Chemical Communications, 2013, 49(42): 4848–4850 https://doi.org/10.1039/c3cc41414k
21	X Fu. Preparation of silicon quantum dots its application in anti-counterfeiting. Wuhan University, 2019
22	A Tang , Y Liu , Q Wang , R S Chen , W Y Liu , Z Q Fang , L S Wang . A new photoelectric ink based on nanocellulose/CdS quantum dots for screen-printing. Carbohydrate Polymers, 2016, 148: 29–35 https://doi.org/10.1016/j.carbpol.2016.04.034
23	R Sliz , M Lejay , J Z Fan , M J Choi , S Kinge , S Hoogland , T Fabritius , F P G De Arguer , E H Sargent . Stable colloidal quantum dot inks enable inkjet-printed high-sensitivity infrared photodetectors. ACS Nano, 2019, 13(10): 11988–11995 https://doi.org/10.1021/acsnano.9b06125
24	X Hou , G Chen , T Xing , Z Z Wei . Reactive ink formulated with various alcohols for improved properties and printing quality onto cotton fabrics. Journal of Engineered Fibers and Fabrics, 2019, 14: 1925957988 https://doi.org/10.1177/1558925019849242
25	B Tawiah , E K Howard , B K Asinyo . The chemistry of inkjet inks for digital textile printing—review. International Journal of Management. Information Technology and Engineering, 2016, 4(5): 61–78
26	T Ghosh , S Nandi , S K Bhattacharyya , S K Ghosh , M Mandal , P Banerji , N C Das . Nitrogen and sulphur doped carbon dot: an excellent biocompatible candidate for in-vitro cancer cell imaging and beyond. Environmental Research, 2023, 217: 114922 https://doi.org/10.1016/j.envres.2022.114922
27	T Ghosh , T K Das , P Das , P Banerji , N C Das . Current scenario and recent advancement of doped carbon dots: a short review scientocracy update (2013–2022). Carbon Letter, 2022, 32(4): 953–977 https://doi.org/10.1007/s42823-022-00339-5
28	R Atchudan , T N J I Edison , S Perumal , R Vinodh , Y R Lee . Betel-derived nitrogen-doped multicolor carbon dots for environmental and biological applications. Journal of Molecular Liquids, 2019, 296: 111817–111817 https://doi.org/10.1016/j.molliq.2019.111817
29	R Atchudan , T N J I Edison , S Perumal , N Muthuchamy , Y R Lee . Hydrophilic nitrogen-doped carbon dots from biowaste using dwarf banana peel for environmental and biological applications. Fuel, 2020, 275: 117821 https://doi.org/10.1016/j.fuel.2020.117821
30	R Atchudan , S C Kishore , P Gangadaran , T N J I Edison , S Perumal , R L Rajendran , M Alagan , S Al-Rashed , B C Ahn , Y R Lee . Tunable fluorescent carbon dots from biowaste as fluorescence ink and imaging human normal and cancer cells. Environmental Research, 2022, 204: 112365 https://doi.org/10.1016/j.envres.2021.112365
31	S Fang , Z Guan , C Su , W S Zhang , J Zhu , Y W Zheng , H B Li , P P Zhao , X H Liu . Accurate fish-freshness prediction label based on red cabbage anthocyanins. Food Control, 2022, 138: 109018 https://doi.org/10.1016/j.foodcont.2022.109018
32	L Guo , T Wang , Z Wu , J W Wang , M Wang , Z Q Cui , S B Ji , J F Cai , C L Xu , X D Chen . Portable food‐freshness prediction platform based on colorimetric barcode combinatorics and deep convolutional neural networks. Advanced Materials, 2020, 32(45): 2004805 https://doi.org/10.1002/adma.202004805
33	A Dager , T Uchida , T Maekawa , M Tachibana . Synthesis and characterization of mono-disperse carbon quantum dots from fennel seeds: photoluminescence analysis using machine learning. Scientific Reports, 2019, 9(1): 14004 https://doi.org/10.1038/s41598-019-50397-5
34	R Atchudan , P Gangadaran , T N J I Edison , S Perumal , A K Sundramoorthy , R Vinodh , R L Rajendran , B C Ahn , Y R Lee . Betel leaf derived multicolor emitting carbon dots as a fluorescent probe for imaging mouse normal fibroblast and human thyroid cancer cells. Physica E, Low-Dimensional Systems and Nanostructures, 2022, 136: 115010 https://doi.org/10.1016/j.physe.2021.115010
35	X Fu , G Li , S Cai , H Yang , K Lin , M He , J W Wen , H B Li , Y B Xiong , D Z Chen . et al.. Color-switchable hybrid dots/hydroxyethyl cellulose ink for anti-counterfeiting applications. Carbohydrate Polymers, 2021, 251: 117084 https://doi.org/10.1016/j.carbpol.2020.117084
36	K Jiang , S Sun , L Zhang , Y Lu , A G Wu , C Z Cai , H W Lin . Red, green, and blue luminescence by carbon dots: full-color emission tuning and multicolor cellular imaging. Angewandte Chemie International Edition, 2015, 54(18): 5360–5363 https://doi.org/10.1002/anie.201501193
37	X Yang , Z T Pan , Y Ma . Rhoda mine B as standard substance to measure the fluorescence-quantum yield of dichlorofluorescein. Journal of Analytical Sciences, 2003, 19(6): 588–589
38	C Li , H You , Z Zhang , Z Q Dai , J T Guan , B M Wei . Synthesis and optoelectronic properties of an arylamine-endcapped spirofluorene for blue light emission. Organic Chemistry, 2011, 31(12): 2095–2101 (in Chinese)
39	R A Velapoldi , H H Tnnesen . Corrected emission spectra and quantum yields for a series of fluorescent compounds in the visible spectral region. Journal of Fluorescence, 2004, 14(4): 465–472 https://doi.org/10.1023/B:JOFL.0000031828.96368.c1
40	Y Zheng , X Li , Y Huang , H B Li , L Y Chen , X H Liu . Two colorimetric films based on chitin whiskers and sodium alginate/gelatin incorporated with anthocyanins for monitoring food freshness. Food Hydrocolloids, 2022, 127: 107517 https://doi.org/10.1016/j.foodhyd.2022.107517
41	B S Dissing , O S Papadopoulou , C Tassou , B K Ersboll , J M Carstensen , E Z Panagou , G J Nychas . Using multispectral imaging for spoilage detection of pork meat. Food and Bioprocess Technology, 2013, 6(9): 2268–2279 https://doi.org/10.1007/s11947-012-0886-6
42	R Ullah , S Khan , H Ali , M Bilal . Potentiality of using front face fluorescence spectroscopy for quantitative analysis of cow milk adulteration in buffalo milk. Spectrochimica Acta. Part A: Molecular and Biomolecular Spectroscopy, 2020, 225: 117518 https://doi.org/10.1016/j.saa.2019.117518
43	P Waligorski , M Szaleniec . Prediction of white cabbage (Brassica oleracea var. capitata) self-incompatibility based on neural network and discriminant analysis of complex electrophoretic patterns. Computational Biology and Chemistry, 2010, 34(2): 115–121 https://doi.org/10.1016/j.compbiolchem.2010.03.002
44	K Chumachenko , A Iosifidis , M Gabbouj . Feedforward neural networks initialization based on discriminant learning. Neural Networks, 2022, 146: 220–229 https://doi.org/10.1016/j.neunet.2021.11.020
45	X Xiao , S Cao , L Wang , S L Cheng , E R Yuan . Deep hashing image retrieval based on hybrid neural network and optimized metric learning. Knowledge-Based Systems, 2024, 284: 111336 https://doi.org/10.1016/j.knosys.2023.111336
46	W Rawat , Z Wang . Deep convolutional neural networks for image classification: a comprehensive review. Neural Computation, 2017, 29(9): 2352–2449 https://doi.org/10.1162/neco_a_00990
47	X Zhang , C Chen , D Peng , Y Z Zhou , J L Zhuang , X J Zhang , B F Lei , Y L Liu , C F Hu . pH-responsive carbon dots with red emission for real-time and visual detection of amines. Journal of Materials Chemistry. C, Materials for Optical and Electronic Devices, 2020, 8(33): 11563–11571 https://doi.org/10.1039/D0TC02597F
48	G Somaraj , S Mathew , T Abraham , K G Ambady , C Mohan , B Mathew . Nitrogen and sulfur co-doped carbon quantum dots for sensing applications: a review. ChemistrySelect, 2022, 7(19): e202200473 https://doi.org/10.1002/slct.202200473
49	A Khan , P Ezati , J W Rhim , J T Kim , R Molaei . pH-sensitive green tea-derived carbon quantum dots for real-time monitoring of shrimp freshness. Colloids and Surfaces. A, Physicochemical and Engineering Aspects, 2023, 666: 131242 https://doi.org/10.1016/j.colsurfa.2023.131242
50	Z Guo , J Luo , Z Zhu , Z S Sun , X G Zhang , Z C Wu , F W Mo , A X Guan . A facile synthesis of high-efficient N,S co-doped carbon dots for temperature sensing application. Dyes and Pigments, 2020, 173: 107952 https://doi.org/10.1016/j.dyepig.2019.107952
51	M M Tang , C Chen , J Z Song , Y B Ni , B Xiang , J Zou , D K Xu . Safety of plant fiber-based food contact materials: overview of the discovery, identification, detection and risk assessment of unknown risk substances. Food Packaging and Shelf Life, 2024, 43: 101281 https://doi.org/10.1016/j.fpsl.2024.101281
52	J V Kumar , J W Rhim . Fluorescent carbon quantum dots for food contaminants detection applications. Journal of Environmental Chemical Engineering, 2024, 12(2): 111999 https://doi.org/10.1016/j.jece.2024.111999

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